Aspirin Use Linked to Wider Retinal Arteriolar Diameters

Pippa Wysong

May 04, 2005

May 4, 2005 (Fort Lauderdale) — People who are regular users of aspirin have wider retinal arteriolar diameters than nonusers showing that the drug has an effect on small vessels.

The finding comes from the Blue Mountains Eye Study, a population-based study of eye health and age-related macular degeneration in the area of the Blue Mountains in Australia.

The study includes data from more than 4,000 people who live in the area, according to Gerald Liew, MD, from the University of Sydney, Australia. Dr. Liew presented findings in a poster at the recent annual meeting of the Association for Research in Vision and Ophthalmology.

"Narrowed vessels in the eye correspond to narrowed vessels elsewhere in the body, and therefore are linked with stroke, heart attack and renal disease which are the main vascular diseases," Dr. Liew said. Narrowed vessels may be something ophthalmologists can watch for, and potentially refer patients who may be at risk for vascular disease.

Wide vessels, on the other hand "improves blood flow...in general wider vessels are considered to be better for the circulation," Dr. Liew said.

"The medical literature abounds with research on the effects of aspirin on large vessels, but there are not many studies on the effects of aspirin on small vessels. This is one of the first studies of small vessels," Dr. Liew said.

People in the study underwent retinal photographs, were interviewed about medication use, and had their medical histories taken. Retinal arterioral widths were determined using standard computer programs designed for this.

In the data presented, a total of 740 were regular aspirin users, and 2,300 were not regular users. Regular use was defined as anywhere from daily to weekly use, and nonregular users took aspirin less frequently.

"What we found was that people who took aspirin regularly had wider arterioles than those who did not. This is a good effect because narrowed arterioles are associated with things like stroke, heart attack, heart failure and peripheral vascular disease," Dr. Liew said. There was also a trend for arterioles being wider in people who were using antihypertensive treatments in addition to aspirin.

"What we think is going on is aspirin plus antihypertensive medications are helping the arteries, the blood vessels in the eye, and possibly helping the blood vessels in the brain and heart as well," Dr. Liew said.

"Overall, the effects on the retinal vessels were modest in the regular aspirin users. Compared with nonaspirin users, vessels were just more than 1% wider. Large structural changes due to a medication would not be expected," Dr. Liew said.

"The main significance of what we found is that aspirin affects the small vessels in a measurable way, which to our knowledge hasn't really been found before. Most research is focused on the large vessels," Dr. Liew said.

The study was funded by the National Health and Medical Research Council of Australia.

ARVO 2005 Annual Meeting: Abstract B827. Presented May 3, 2005.

Reviewed by Gary D. Vogin, MD